Your question is Optimizing an Existing Application. Take a moment with it on the right.
Talk me through your thinking if you like. When you're confident, submit your answer and I'll grade it like a real screen (7/10 or better passes).
Describe a situation where you optimized an existing application.
Explain the application's baseline problems, how you identified the primary bottleneck, and how you evaluated competing optimization options. Cover your implementation approach, coordination with relevant stakeholders, validation and rollout plan, risks managed, and measurable results. Be clear about the trade-offs between performance, reliability, maintainability, delivery speed, and user impact.